Sea of Shadows

Sea of Shadows is a 2019 Austrian documentary about environmental activists, the Mexican Navy, marine scientists and undercover investigators trying to prevent the extinction of the vaquita, a species of porpoise and the smallest whale in the world, by pulling gillnets, doing research, and fighting back Mexican cartels and Chinese mafia who are destroying ocean habitats in their brutal pursuit to harvest the swim bladder of the totoaba fish, known as the "cocaine of the sea". The 1 hour and 44 minutes long film is directed by Richard Ladkani.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.